configure: fix run-compiler for old /bin/sh

If you try to assign and export on the same line on some older /bin/sh
implementations, it complains:

```
$ export "NAME=value"
NAME=value: is not an identifier
```

This commit rewrites run-compiler's assignments and exports to work with
old /bin/sh, splitting assignment and export into two separate
statements, and only quote the value. So now we have:

```
NAME="value"
export NAME
```

While we're here, make the same change to the two supporting
assign+export lines preceeding the script to be consistent with how
exports work throughout the rest of configure.ac.

Closes #11228

diff --git a/configure.ac b/configure.ac
index b358f9a1fa4af21fc772d39dea37b3f3dbb2fea7..02ad622f2cb717bda94f2923ce0c7696fbbb6e09 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -193,11 +193,15 @@ dnl something different but only have that affect the execution of the results
 dnl of the compile, not change the libraries for the compiler itself.
 dnl
 compilersh="run-compiler"
-export "CURL_SAVED_CC=$CC"
-export "CURL_SAVED_LD_LIBRARY_PATH=$LD_LIBRARY_PATH"
+CURL_SAVED_CC="$CC"
+export CURL_SAVED_CC
+CURL_SAVED_LD_LIBRARY_PATH="$LD_LIBRARY_PATH"
+export CURL_SAVED_LD_LIBRARY_PATH
 cat <<\EOF > "$compilersh"
-export "CC=$CURL_SAVED_CC"
-export "LD_LIBRARY_PATH=$CURL_SAVED_LD_LIBRARY_PATH"
+CC="$CURL_SAVED_CC"
+export CC
+LD_LIBRARY_PATH="$CURL_SAVED_LD_LIBRARY_PATH"
+export LD_LIBRARY_PATH
 exec $CC "$@"
 EOF